Pack variants for heating or cooling, especially for use on the human body, have been known for a long time. In most cases, these packs comprise an interior compartment, normally containing water, and an exterior compartment, containing, for example, a salt. When pressure is exerted onto the interior compartment, its wall tears open, whereby the water which gets into contact with the salt causes, depending upon the type of salt, an exothermal or endothermal reaction. For example, EP 454912 describes a cooling pack in which the separated compartments contain an ammonium salt and urea, if necessary, in order to achieve a very good cooling effect.
U.S. Pat. No. 4,049,408 discloses a cooling pack for blood samples in which double-compartment containers containing ammonium nitrate in one compartment and water in the other compartment and being integrated in a wrappable cover are, after bringing together the two reacting components, wrapped around a cylindrical blood sample thus ensuring its cooling.
A hot pack to be applied on the human body is known from U.S. Pat. No. 4,057,047 in which water contained in an interior compartment having a perforation and water-free magnesium sulphate in a tightly sealed exterior compartment are brought into contact with each other. The exothermal reaction is used, for example, to warm up limbs of sportsmen in winter.
It is an objective of the present invention to provide a pack unit comprising several compartments which may be used to quickly and effectively heat or cool a product on the basis of a chemical reaction in the compartments with the pack unit being at the same time simple to handle and to manufacture.
The multi-compartment pack comprises a first compartment containing a solid matter or a liquid and an adjacent second compartment temporarily separated from said first compartment and containing a liquid, wherein, if the temporary separation of said compartments is eliminated, the substances in both compartments get into contact with each other and cause an endothermal or exothermal reaction, said pack being characterized according to the present invention in that at least one wall of the first compartment and one wall of the second compartment form at the same time a permanent whole contact area to a third compartment, which contains a product to cool or to heat; the first compartment and the second compartment are in contact with the third compartment solely via the contact area; the liquid present in both compartments after interrupting the separation at a sealing between the first compartment and the second compartment makes possible an interchange of heat by transfer via the whole contact area to the third compartment; and the third compartment comprises an opening easily to be opened from the outside from which the heated or cooled product can be taken out following the reaction between the substances contained in the first and second compartments.